NSF-funded research team analyzes seismic response of landfills (with videos)

LOS ANGELES — More than 300 million tons of trash is tossed away each year in the U.S., and approximately 69 percent of the waste goes to landfills. To ensure future municipal landfills are well-engineered to be structurally and environmentally safe, Cal State L.A.’s Civil Engineering Professor Mark Tufenkjian and a team of fellow engineers have been working collaboratively on research regarding seismic properties of municipal solid waste.

“Since California is in an earthquake zone, it is relevant for the research to take place here,” said Tufenkjian. “People don’t realize there is a lot involved in designing landfills, particularly the containment and the cover. It is important to make the landfills earthquake resistant, as they have to sit there not only during operation, but also, long term, when they have to be maintained.”

According to a recently-produced video, which was featured in Geoengineer.com, this research project is the first time that engineers are able to test waste in such a large and controlled environment, where they can simulate shaking on site and then carefully instrument the behavior.

The team’s work, which is funded by the National Science Foundation (NSF), uses a new method to assess the dynamic properties of the municipal solid waste in the field. It describes the method as utilizing large mobile shakers available at the Network for Earthquake Engineering Simulation (NEES) of the University of Texas.

Professor Tufenkjian, who is a co-principal investigator of the NSF grant, and his graduate student Ruwanka Purasinghe have conducted testing on the currently closed BKK landfill in West Covina, Calif. They are now studying the highly variable core samples to determine soil dynamics, soil properties and soil strength in the laboratory, and comparing the results with the field testing.

The research project, formally named “Seismic Response of Landfills: In-situ Evaluation of Dynamic Properties of Municipal Solid Waste, Comparison to Laboratory Testing, and Impact on Numerical Analyses,” aims to develop better seismic guidelines for designing these landfills against future earthquakes. Data from the project will soon be archived and made available to the public through the NEES data repository.

In addition to Tufenkjian and Purasinghe, the research team includes Dimitrios Zekkos and Richard W. Woods of the University of Michigan, Ann Arbor; Neven Matasovic of Geosyntec Consultants; and Kenneth Stokoe II of the University of Texas.

Purasinghe, a civil engineering major, believes that the project, which combines geotechnical and environmental engineering, has taught him a lot about the research process and conducting lab experiments at the higher education level. “It’s definitely enlightening for me,” said Purasinghe, “and I hope that the lessons learned from this experiment can be utilized to better assess other landfills for earthquake safety throughout Southern California.”

At CSULA, Tufenkjian is in charge of the geotechnical engineering program and teaches all geotechnology-related courses at the undergraduate and graduate level in the Department of Civil Engineering. He is a registered civil engineer in the state of California. Previously, Tufenkjian was a geotechnical engineer for several prestigious firms, where he worked on a wide array of projects of varying complexity over land and water as an engineer and project manager. With his expertise in geotechnical engineering, Tufenkjian is also the primary investigator for the University’s Naval Seafloor Engineering Research Program, funded by the U.S. Navy Department.

“The research will develop a mini-cone penetration system for determining seafloor soil properties to assist in the design of foundations and mooring elements,” said Tufenkjian. “This is also another opportunity for CSULA students to obtain exciting research experience in the field of civil engineering.”